ATI RN
microbiology chapter 12 test bank Questions
Question 1 of 9
A patient presents with diarrhea and dehydration. A fecal smear stained by Gram's method revealed Gram-negative, comma-shaped bacteria. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Vibrio cholerae. Vibrio cholerae is the causative agent of cholera, which presents with severe watery diarrhea leading to dehydration. The characteristic comma-shaped (curved rod) appearance of Gram-negative bacteria is typical of Vibrio cholerae. This bacterium produces the cholera toxin, leading to the excessive secretion of fluid into the intestines. Salmonella typhi causes typhoid fever with symptoms like sustained fever, not watery diarrhea. Shigella dysenteriae causes bloody diarrhea and abdominal cramps. Escherichia coli can cause various types of infections, but typically not severe watery diarrhea like cholera.
Question 2 of 9
Which bacterium is known for causing food poisoning due to its production of enterotoxins?
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus aureus. This bacterium causes food poisoning by producing enterotoxins that lead to symptoms like nausea and vomiting. Staphylococcus aureus can survive in various food items and multiply rapidly, producing toxins that are heat-stable. Clostridium botulinum causes botulism due to neurotoxins, not enterotoxins. Salmonella enterica causes gastrointestinal infections, not primarily food poisoning. Vibrio cholerae causes cholera by producing a toxin that leads to severe watery diarrhea and dehydration, not enterotoxins like Staphylococcus aureus.
Question 3 of 9
The first grade pupils were examined in order to sort out children for tuberculosis revaccination. What test was applied for this purpose?
Correct Answer: A
Rationale: The correct answer is A: Mantoux test. The Mantoux test is used to detect tuberculosis infection by injecting a small amount of tuberculin under the skin and checking for a reaction. This test helps identify individuals who have been exposed to tuberculosis. The other choices are incorrect because: B: Schick test is used to determine immunity to diphtheria, not tuberculosis. C: Anthraxine test is used for anthrax, not tuberculosis. D: Burnet test is not a recognized medical test for tuberculosis.
Question 4 of 9
Which of the following bacteria is known for producing a neurotoxin that causes paralysis?
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the botulinum neurotoxin, which causes paralysis by blocking the release of acetylcholine at neuromuscular junctions. Clostridium perfringens causes gas gangrene, not paralysis. Escherichia coli is associated with gastrointestinal infections, not paralysis. Staphylococcus aureus produces enterotoxins causing food poisoning, not paralysis. Therefore, Clostridium botulinum is the correct choice based on its well-known association with paralysis due to botulinum neurotoxin production.
Question 5 of 9
Impression smear of mucosa biopsy material has been obtained from a patient with peptic ulcer disease of the stomach. Gram-negative arcuate bent microorganisms were detected, urease activity test was positive. What microorganisms were detected in the patient?
Correct Answer: A
Rationale: The correct answer is A: Helicobacter. Helicobacter pylori is the main causative agent of peptic ulcer disease and is characterized by its gram-negative arcuate bent shape and positive urease activity. Helicobacter pylori specifically colonizes the stomach mucosa and is associated with various gastrointestinal disorders. Spirochetes (choice B), spirilla (choice C), and Leptospira (choice D) are not typically associated with peptic ulcer disease or stomach mucosa infections, making them incorrect choices in this context.
Question 6 of 9
For treatment of Anthrax are used
Correct Answer: D
Rationale: The correct answer is D because the treatment for Anthrax involves using antibiotics such as penicillins, tetracyclines, and macrolides to target the bacteria. Anti-anthrax gamma-globulins and immune-serum are used to provide passive immunity, but they are not the primary treatment. Therefore, options A, B, and C are incorrect as they do not encompass all the necessary components for treating Anthrax. Overall, using a combination of antibiotics and immune-based treatments like gamma-globulins and immune-serum provides a comprehensive approach to managing Anthrax infection.
Question 7 of 9
A 10-year-old child had the mantoux tuberculin test administered. 48 hours later a papule up to 8 mm in diameter appeared on the site of the injection. What type of hypersensitivity reaction developed after the tuberculin injection?
Correct Answer: A
Rationale: The correct answer is A: Type IV hypersensitivity reaction. This type of reaction is characterized by a delayed response involving T cells. In this case, the appearance of a papule after 48 hours indicates a delayed hypersensitivity reaction, which is typical of a Type IV reaction. The other choices are incorrect because: B: Arthus phenomenon is a localized immune complex-mediated reaction, not seen in tuberculin tests. C: Seroreaction typically involves antibodies reacting with soluble antigens, not seen in this scenario. D: Type II hypersensitivity reactions involve antibodies targeting specific cells or tissues, which is not the mechanism at play in this case.
Question 8 of 9
A fecal smear from a patient with chronic diarrhea revealed cysts with four nuclei. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Entamoeba histolytica. The presence of cysts with four nuclei is characteristic of Entamoeba histolytica, a protozoan parasite causing amoebic dysentery. It forms cysts with four nuclei before maturing into trophozoites. Balantidium coli (B) is a ciliated protozoan causing balantidiasis, not known for four-nuclei cysts. Giardia lamblia (C) forms cysts with two nuclei, causing giardiasis. Trichomonas hominis (D) is a non-pathogenic flagellate found in the human colon, not associated with four-nuclei cysts.
Question 9 of 9
Micellar growth
Correct Answer: D
Rationale: Step 1: Micellar growth refers to the apical prolongation of hyphae in fungi. Step 2: Fungi have a unique growth structure with hyphae extending at the tips. Step 3: This growth pattern allows fungi to expand and access nutrients. Step 4: Bacterial cells (A) do not exhibit micellar growth. Step 5: Parent and daughter cells in division have similar sizes, not different (B). Step 6: Viruses and rickettsia (C) do not display micellar growth.